Passenger elevators began as a convenience in the early 1900s, but have since grown in popularity. In addition to convenience, elevators are now required by law in many new buildings. Given these expectations, the number of elevators currently in service in the United States is approaching one million, with the overwhelming majority of these elevators having been installed within the last fifty years.
Elevators are high traffic areas and are often utilized most by as occupants and visitors are coming and going from a building, particularly in the case of a commercial building, such as an office tower. Accordingly, building owners and their interior designers are frequently looking to present an appealing fit and finish within the interior of their elevators. Furthermore, after a certain period of time, the interior of an elevator cab needs to be renovated due to wear and tear or simply to update its look to match that of the rest of the building's interior. To accomplish such an update to an elevator, retrofit kits are custom made which include a number of panels and decorative items. These kits can be installed in place of the original interior within the elevator cab.
One common accessory included within the interior of most elevators is a handrail. Mounting the handrail securely must be done properly to ensure that the handrail is structurally secure. Traditional methods of retrofitting a handrail require that the installer have access to the exterior of the cab in order to secure fasteners to the end of bolts passing through the cab's wall from the interior or vice versa.
To access the exterior of the elevator cabin, the installer generally must access the elevator shaft. The elevator shaft can be a hazardous location, especially in the case of the retrofit of new handrails to an existing elevator. In this case, the elevator shaft can have accumulated much dirt, grime, or slippery surfaces (such as from lubricant). The elevator shaft can alternatively contain allergens, mold, or other health hazards. If the building is of sufficient age, the elevator shaft can also contain asbestos. In these cases, installers will be required to wear protective equipment which increases costs associated with the handrail installation and makes the process more cumbersome. In addition, in some situations, specialized laborers and/or authorized representatives of the elevator manufacturer are required to access the elevator shaft. Conversely, the interior of elevator cabins easy to access and are generally well maintained so as to comply with safety standards and to appease the users of the elevators.
Having the ability to install a handrail from the interior of the elevator cabin generally reduces the amount of labor required to replace elevator handrails, regardless of the conditions of the elevator shaft. The use of a nut or other capture device on the exterior of the elevator generally requires the installation personnel to be positioned on the exterior of the elevator, especially in the case of a retrofit. Some elevators have capture devices mounted directly into their side walls, but at times it may be desirable to install new capture devices at new locations or the mounted capture device may periodically require replacement, such as if they are old and have seized.
In the case that a capture device is added to the exterior of the elevator cabin, additional personnel may be needed as opposed to a system where the work can be performed from solely within the cabin. This is because an individual is needed to hold the nut from outside of the cabin and another is needed to thread a corresponding member into the nut from the interior of the cabin.
Additionally, the bolts used to secure the fasteners can loosen over time due to use by persons and vibrations from the travel of the elevator. It is preferable to have a mechanism by which the installation and tightening of a retrofit handrail can be accomplished while working solely from the interior of the elevator cab. Additionally, it is desirable to prevent loosening of the handrail as it is used over time.